MUST WATCH

Story highlights

Clinton says Trump is hypocritical for claiming that the Clinton Foundation is a pay-to-play scheme

White Plains, New York (CNN)For Bill Clinton, critiques of Donald Trump's foundation for an illegal donation to the Florida attorney general is more than just politics, aides and friends say. It's about defending what he considers his considers his post-presidential life work: The Clinton Foundation.

"My charity helps people, his is used to pay off your attorney general," Clinton said Wednesday in Orlando.

After spending months out of the public eye -- primarily fundraising for his wife's campaign -- the former President has used a series of campaign events to call Trump hypocritical for claiming that the Clinton Foundation is a pay-to-play scheme while the Republican nominee's foundation was fined by the IRS for donating $25,000 to a political group supporting Pam Bondi's 2014 reelection bid.

"President Clinton has decided to stand up against Trump and the cynics driving a political agenda," an aide said.

Trump's donation came days after Bondi's office said it was weighing an investigation into allegations of fraud against the scandal-ridden Trump University. No investigation was ever opened, and Bondi denies any connection between that decision and Trump's donation.

Read More

In North Carolina on Tuesday, Bill Clinton said that he got "tickled the other day when Mr. Trump called my foundation a criminal enterprise."

"He made a political contribution to the attorney general of Florida who at the time had her office investigating Trump University," Clinton added. "And mysteriously, the investigation vanished."

Hillary Clinton's campaign has been trying to draw more attention to the controversy surrounding Trump's foundation, routinely noting a disparity in coverage between the two foundations.

What they have found: Bill Clinton, whose own foundation has drawn political criticism, may be their best messenger.

Bill Clinton's spokesman said refuting Trump in the battle over the foundations was personal for the former world leader.

"For the last 15 years, the work of the Clinton Foundation and the people who rely on it have been President Clinton's life," said Angel Urena, Clinton's spokesman. "So when someone who doesn't know the first thing about philanthropy tries to bring the Clinton Foundation into his political sideshow, President Clinton is going to stand up for it."

For years, the Clinton Foundation has drawn intense scrutiny from journalists, right-wing watchdogs and candidates like Trump, who described the charity a "vast criminal enterprise" last month and has called for a special prosecutor to investigate Hillary Clinton's connection to the foundation.

Clinton's aides have tried to push back against these attacks and charity watchdog organizations have rated the Clinton Foundation highly this year.

Brian Fallon, Clinton's national press secretary has permanently fixed one tweet to the top of his account: Charity watchdog declares to CNN that @ClintonFdn is "one of the great humanitarian charities of our generation."